(a) Field of the Invention
The present invention relates to a finisher for smoothly finishing the surface of a concrete floor while moving the machine proper on the floor subjected to concrete placing and more particularly to such finisher which is applicable to both the unmanned automatic operation system capable of freely performing the work by automatic operation or remote operation without manning the machine and the manned manual operation system adapted for manning the machine to perform the work by manual operation.
(b) Description of the Prior Art
In view of the problems encountered with such concrete-floor finisher of the manned manual operation system as disclosed in Japanese Laid-Open Patent Application No. 63-130860, e.g., the increased weight, the deteriorated operability and the increased labor and longer term of operation, the inventors have made efforts toward the development of an unmanned-type machine capable of automatic operation and its basic construction has been made known by Japanese Laid-Open Patent Applications No. 4-261960, No. 5-5357 and No. 6-93729.
This concrete-floor finisher of the unmanned automatic operation system includes a pair of rotors each having a plurality of radially attached blades (or otherwise referred to as trowels) and the rotary shaft of each rotor is tiltably mounted on the machine proper. The machine proper is supported on a concrete flower surface by the plurality of blades whereby the rotary shafts of the pair of rotors are each tilted in a given direction while rotating the blades by the rotors in the opposite directions so as to increase the pressure exerted on the concrete floor surface by each blade and generate a propulsive force in the opposite direction to the rotational direction of the blade existing in the position of the increased pressure thereby causing the machine proper to move or turn in a given direction so as to smoothly finish the concrete floor surface. This travelling principle is the same with the manned manual operation system.
However, the condition of the placed concrete floor surface is not uniform but involves irregularities, slopes or inclines, undulations, etc., with the result that any effort to move the machine proper straight ahead tends to cause the machine proper to turn in any given direction or make a turning motion. As a result, an attempt has been made to ensure the straight-forwardness of the movement by providing the operating rod or the rotary shafts with any tilting correction amounts of the cancelling directions and this operation has been found to be extremely difficult.
In addition, the travelling performance, moving controllability or operability of the machine proper, the finishing quality of the concrete floor surface, etc., have been greatly influenced by the methods of arrangement of the blades disposed on the right and left rotors, particularly the pressure points where the pressures exerted on the concrete floor due to the tilting of the blades (hereinafter referred to as the points of application of pressure).
As shown in FIGS. 16a-16d, for example, if the blades 12a to 12d of the right and left rods are arranged apart so that their outer peripheral circles (or the rotational paths of the outer peripheral ends of the blades) 12e do not cross each other as shown in FIG. 16a, although the travelling performance is stabilized, there results a gap between the right and left blade outer peripheral circles 12e so that an unfinished part is left in this portion and it is required to repeatedly move the machine proper a number of times thus requiring an extremely long finishing time. Thus, the usual practice is to arrange the right and left blades in such a manner that their outer peripheral circles 12e cross each other as shown in FIG. 16b or FIG. 16c. In this case, if the amount of crossing of the blade outer peripheral circles 12e is small as shown in FIG. 16b, a projection portion 100 of the stripe-like raised concrete is caused in the central portion (FIG. 16d) thus ruining the finishing quality. On the other hand, if the amount of crossing of the blade outer peripheral circles 12e is increased considerably as shown in FIG. 16c, while no such projection portion as mentioned above is caused, the travelling performance becomes unstable and also the mobile control and operation become difficult. Since the condition of the concrete surface involves irregularities, slopes, etc., as mentioned previously, the straight-ahead travelling performance is deteriorated and the machine proper is caused to turn to the left or right. While a corrective turning is imparted to the machine proper for correcting such turning movement, the turning performance of the machine proper is greatly dependent on the positions of the points application of the blades and thus these control and operation are extremely difficult.
In view of these circumstances, irrespective of the manned type and the unmanned type, the conventional concrete-floor finishers have the disadvantages of being difficult to operate and requiring a long period of time (about one year) for the training of operators.